• 대한화학회지
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• 제42권1호
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• pp.9-15
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• 1998

Dimethyldioxirane$[(CH_3)_2CO_2]$의 분자구조, vibrational frequencies 그리고 infrared(IR) 스펙트럼의 세기(intensity)등에 대한 이론적 연구를 high level ab initio 양자역학적 방법(CISD,CCSD, CCDS(T))을 사용하여 수행하였다. 분자구조의 경우 C-O와 O-O에 대한 결합길이는 parent dixoirane$(CH_2O_2)$과 유사한 결과를 보여주었으며, electron correlation effect의 영향이 C-C나 C-H결합길이 보다 더 크게 작용하였다. 사용된 basis sets(DZ,DZP, TZP, 그리고 TZ2P)에 대해서는 polarization function의 역할이 매우 중요한 것으로 나타났으며 triple zeta(TZ)에 의한 효과는 상대적으로 나타났다. 한편 계산된 harmonic vibrational frequency들을 실험결과 및 다른 이론 계산결과와 비교, 분석하였으며 IR intencity에 근거하여 각 vibrational mode를 assign하였다.

• Toxicological Research
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• 제29권3호
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• pp.203-209
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• 2013

A simple and rapid liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated for the quantification of ${\varepsilon}$-acetamidocaproic acid (AACA), the primary metabolite of zinc acexamate (ZAC), in rat plasma by using normetanephrine as an internal standard. Sample preparation involved protein precipitation using methanol. Separation was achieved on a Gemini-NX $C_{18}$ column ($150mm{\times}2.0mm$, i.d., 3 ${\mu}m$ particle size) using a mixture of 0.1% formic acid-water : acetonitrile (80 : 20, v/v) as the mobile phase at a flow rate of 200 ${\mu}l/min$. Quantification was performed on a triple quadrupole mass spectrometer employing electrospray ionization and operating in multiple reaction monitoring (MRM) and positive ion mode. The total chromatographic run time was 4.0 min, and the calibration curves of AACA were linear over the concentration range of 20~5000 ng/ml in rat plasma. The coefficient of variation and relative error at four QC levels were ranged from 1.0% to 5.8% and from -8.4% to 6.6%, respectively. The present method was successfully applied for estimating the pharmacokinetic parameters of AACA following intravenous or oral administration of ZAC to rats.

• Journal of Yeungnam Medical Science
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• 제3권1호
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• pp.1-11
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• 1986

As public awareness of the various warning signs of malignancy increases, so does the concern evoked by the self identified finding of mass in the head and neck area. Not all the palpable masses are always significantly abnormal, but any nontender mass especially to the adult is significant enough to warrent further full investigation and follow up, the object of which should be to determine the possibility of malignancy and urgency of treatment. Approach to the diagnosis of the neck mass is so important in that it affects decision regarding further evaluation would lead to the determination of the most efficacious mode of therapy, eventually to the good prognosis. So, it should be emphasized that approach to the diagnosis of neck mass should be planned, systematic and thorough, this begins with the taking careful history following performance of complete examination of the head and neck especially to the nasopharynx, tongue base, pyriform sinus, palatine tonsil and larynx. Then a number of laboratory and radiologic studies are available, following triple endoscopy under general anesthesia and blind biopsy if needed. The most important rule to keep is that any biopsy procedures should be delayed to the last modality of effort to the diagnosis and if it should be done, under the plan of radical neck dissection.

• 제어로봇시스템학회논문지
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• 제5권6호
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• pp.647-655
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• 1999

For linear time-varying systems described by the triple (A(t),B(t),C(t)) where A(t),B(t),C(t) are the system, the input, and the output matrices, respectively, we propose concepts for measures of modal and gross controllability /observability. We introduce a differential algebraic eigenbvalue theory for linear time-varying systems to calculate the PD-eigenvalues and left and right PD-eigenvectors of the system matrix A(t) which will be used to derive the concepts for the measures. The time-dependent angle between the left PD-eigenvectors of the system matrix A(t) and the columns of the input matrix B(t), and the magnitude of the each element of the input matrix B(t) are used to propose the modal controllability measure. Similarly, the time-dependent angle between the right PD-eigenvectors of the system matrix A(t) and the rows of the output matrix C(t) are used to propose the madal observability measure. Gross measure of controllability of a mode from all inputs and its gross measure of observability in all outputs for the linear time-varying systems are also proposed. Numerical examples are presented to illustrate the proposed concepts.

• Bulletin of the Korean Chemical Society
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• 제32권2호
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• pp.524-530
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• 2011

In the present study, we demonstrate that SRM LC-MS/MS method developed by Luo et al. (ref. 10) can be successfully applied to the quantitative analysis of intracellular metabolites in E. coli that are collected at the exponential and stationary growth phases. A focus is given on measuring the changes in the concentrations of intracellular metabolites in batch cultures, which were induced during both the dynamically changing exponential and stationary growth phases. The following intracellular metabolites are quantified in the exponential and stationary phases of E. coli growth, using the SRM mode of a triple quadrupole mass spectrometer: glucose-1-phosphate, fructose-1,6-bisphosphate, phosphoenolpyruvate, pyruvate, acetyl-coenzyme A, 6-phosphogluconate, ribulose-5-phosphate, xylulose-5-phosphate, erythrose-4-phosphate. The determined intracellular metabolite concentration profiles are shown to be in a good agreement with the growth profiles of E. coli, which clearly indicates that SRM LC-MS/MS can be successfully used for following the metabolite changes induced at different growth stages.

• 정보처리학회논문지C
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• 제14C권1호
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• pp.7-16
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• 2007

3G 이동통신, 무선랜은 각기 다른 장단점을 가지고 무선 통신 서비스를 제공하고 있다. 현재 이들 서비스의 단점들을 보완하도록 설계한 WiBro 서비스가 개발되었으며. 3중-모드로 작동하는 단말기를 이용하는 사용자가 세 개 망을 편리하게 사용할 수 있도록 하기 위한 3G-WLAN-WiBro 연동 시스템이 제안되었다. 각 망은 보안과 과금을 위하여 사용자와 네트워크간의 상호 인증 절차를 도입하고 있으나, 서로 다른 인증 프로토콜을 사용하고 있다. 본 논문에서는 3G-WLAN-WiBro 연동 네트워크상에서, 사용자가 동일 사업자의 이종 망으로 이동할 때 이전망에서 사용하던 인증 정보를 활용하면서 새로운 망으로 안전하게 로밍할 수 있도록 지원하기 위한 통합된 인증 및 키 관리 프로토콜을 제안하였다.

• Molecules and Cells
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• 제39권2호
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• pp.163-168
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• 2016

Caffeine has both positive and negative effects on physiological functions in a dose-dependent manner. C. elegans has been used as an animal model to investigate the effects of caffeine on development. Caffeine treatment at a high dose (30 mM) showed detrimental effects and caused early larval arrest. We performed a comparative proteomic analysis to investigate the mode of action of high-dose caffeine treatment in C. elegans and found that the stress response proteins, heat shock protein (HSP)-4 (endoplasmic reticulum [ER] chaperone), HSP-6 (mitochondrial chaperone), and HSP-16 (cytosolic chaperone), were induced and their expression was regulated at the transcriptional level. These findings suggest that high-dose caffeine intake causes a strong stress response and activates all three stress-response pathways in the worms, including the ER-, mitochondrial-, and cytosolic pathways. RNA interference of each hsp gene or in triple combination retarded growth. In addition, caffeine treatment stimulated a food-avoidance behavior (aversion phenotype), which was enhanced by RNAi depletion of the hsp-4 gene. Therefore, up-regulation of hsp genes after caffeine treatment appeared to be the major responses to alleviate stress and protect against developmental arrest.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2006년도 춘계학술대회논문집
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• pp.672-675
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• 2006

It is becoming more significant to develop a rotary VCM type actuator for small form factor ODD, as portables are getting more and more popularized nowadays. In this paper, the procedure of development of the actuator which is applicable to compact flash II card and is fit in the specification of BD 1X is explained. This is based on the rotary VCM type actuator, which is good for reducing thickness. Air core solenoid coil is used in order to do focusing mechanism. And the total weight is reduced by using the structure of steel-aluminium-steel triple layer, so, the stiffness is still adequate. Additionally, the tracking coil is moved next to the actuator, so the total length was reduced, then the actuator become applicable to compact flash II card. The force of Magnetic Circuit is improved by using Magnetic Circuit DOE. And flexible mode frequency improved through the DOE of structure part. Modeling was exactly done in consideration of air core solenoid coil and pivot bearing. It is confirmed that the designed model is satisfied with the specification of BD 1X and is applicable to Compact Flash II card.

• Bulletin of the Korean Chemical Society
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• 제35권1호
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• pp.197-203
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• 2014

A rapid, accurate and precise method for the determination of 22 amino acids in Isatidis Radix by Hydrophilic Interaction Ultra-High-Performance Liquid Chromatography Coupled with Triple-Quadrupole Mass Spectrometry (HILIC-UPLC-MS/MS) was established. Chromatographic separation was carried out on a Acquity UPLC BEH Amide column ($2.1mm{\times}100mm$, $1.7{\mu}m$) with gradient elution of acetonitrile (containing 0.05% formic acid and 2 mM ammonium formate) and water (containing 0.15% formic acid and 10 mM ammonium formate) at a flow rate of 0.4 mL/min; Waters Xevo$^{TM}$ TQ worked in multiple reaction monitoring mode. All components were separated in 17 min. All calibration curves were linear ($R^2$ > 0.991) over the tested ranges. The limits of detection (LOD) and limits of quantitation (LOQ) for these compounds were 0.21-79.55 and 0.72-294.23 ng/mL, respectively. The average recoveries were in the range of 93.75-104.16% with RSD value less than 6.56%. Therefore, this method could be an alternative assay for the determination of 22 amino acids in Isatidis Radix due to its rapidness, sensitivity, less sample and solvent consumption.

• Steel and Composite Structures
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• 제34권1호
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• pp.53-73
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• 2020

A novel all-steel miniature bar-type structural fuse (MBSF) with cold formed bolted connections is developed in this study, which consists of a central energy dissipation core cut from a smooth round bar, an external confining tube and nuts. Three types of cross sections for the central energy dissipation core, i.e., triple-cut, double-cut and single-cut cross sections, were studied. Totally 18 specimens were axially tested under either symmetric or asymmetric cyclic loading histories, where the parameters such as cut cross sectional area ratio, length of the yielding portion and cross sectional type were investigated. Numerical simulation of 2 representative specimens were also conducted. An analytical model to evaluate the bending failure at the elastic portion was proposed, and a design method to avoid this failure mode was also presented. The experimental results show that the proposed MBSFs exhibit satisfactory hysteretic performance under both the two cyclic loading histories. Average strain values of 8% and 4% are found to be respectively suitable for designing the new MBSFs as the ultimate strain under the symmetric and asymmetric cyclic loadings.